The Com Hat 1 was the predacessor of the superlites. It used a liquid filled liner to cushion the head and offset the air space / buoyancy problems. Unfortunately the liner tended to leak. The Superlite addressed the problem by using a plain foam liner and adding weights to the helmet to offset the buoyancy. If you take a look at my profile pictures there is a brochure there that describes the Com Hat 1.

Thanks for the compliment on my helmet. Used it for 10 years in the oilfield on air and helium dives. Rarely used demand as it was super quiet(Desco exhaust made more noise than incoming air). Tried KM adjustable regulator, but preferred standard regulator. Chin pad in helmet kept mouthpiece easy to draw air directly from regulator. Just gathering dust now as I don't think anyone is hiring 70 year old divers.